Problems associated with powering grapples and buckets have included slowness of operation by hydraulic means because of the length of hydraulic lines necessary for extending out from the crane to the end of the hoist line. This awkwardness is compounded in situations exhibiting lack of automatic accommodation of the powered jaws, one to the other in closing on a load.
In the known art, the problem has been eased to some extent by provision of a hydraulic power unit on the top of a hydraulically actuated jaw implement such as a clamshell bucket or grapple, and by hydraulic connection in parallel of respective jaw-operating cylinder assemblies.
Also known in the art is a radio-controllable excavator that can be operated almost submerged in water.